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The static recovery of dislocations in aluminium alloys is known to observe during re-heating and inter-annealing of aluminium alloys, so that the fully recrystallised and partially recrystallised grain structures are deliberated respectively for a judicious control on their final tempering of strength, ductility, toughness and crystallographic texture to eliminate the earing related problems. An elaborate physical based static recovery simulator is required to address the trend of dislocation recovery during the time of industrial annealing to evaluate the extent of discontinuously and continuously developed recrystallised aluminium alloys. New industrial annealing practices to develop an extensively wide range of aluminium alloys with the medium to low stacking fault energy range, suitable for their plenty of use in defence vehicles, inevitably demand quantified dislocation density, the decisive element of flow strength. The formulated static recovery rate of the constricted dislocation jogs increases with the stacking fault energy and increases with the industrial annealing temperature. The formulated static recovery of dislocations is found to be very precise and concentric to address the process and materials characteristics, so that it would be liable to define the minute change in the processing temperature, i.e. 50K.

Solid particle erosion of the 52100 bearing steel induced the normal growth of the tempered lath martensite, the low angle boundaries and the recovery islets. Microstructural features were revealed using the electron microscopy. Constitutive equations for the normal growth of the tempered lath martensite, energies of the low angle boundaries, and size of the recovery islets have been derived. The normal growth rate of the tempered lath martensite has been derived from the oriented mobility of the boundary in crystallite-stress fields, the driving force from the boundary energy and the pinning force from the uniformly distributed precipitates. Read-Shockley equation has been redefined using the dislocation density term as the misorientation of the boundary. An advanced Read-Shockley equation has been used for predicting the size of the recovery islets (0.12 mm to 0.27 mm) from the local energy equilibrium of the recovered tempered lath martensite, and validated by the TEM bright field microscopic study.

Know-how of microstructural developments during erosion of 52100 and M50 tribological steels and associated erosion resistance knowledge are required for enhancement of properties. Erosion induced microstructural features such as disintegration of martensite boundaries, normal growth of martensite lath, low angle grain boundaries, shear bands, dislocation cell structure and independent recovery islets. Fraction of low angle grain boundary was larger after oblique erosion of 52100 steel while less shear bands were produced after oblique erosion compared to normal erosion. 52100 steel also developed independent recovery islets with tight packed dislocation wall and recovered cell interior. M50 ferrite developed dislocation cell structure during normal erosion. In general normal impact has been associated with greater erosion resistance. Comparatively less ploughing has increased erosion resistance of M50 ferrite than that of M50 martensite. Normal erosion resistance of 52100 and M50 martensite has been observed to be equal.

Present work describes a correlation among microstructure, texture and mechanical properties anisotropy of ternary Ni–16Cr–16Mo, Ni–16Cr–4W and Ni–16Ce–8Fe alloys in hot rolled and annealed condition. The evolution of microstructures of the alloys has been explained based on stacking fault energy and presence of texture components in the material. The alloys Ni–16Cr–16Mo, Ni–16Cr–4W and Ni–16Cr–8Fe exhibit low, moderate and high values of in-plane anisotropy, respectively. The anisotropy index values of alloys Ni–16Cr–4W, Ni–16Cr–8Fe and Ni–16Cr–16Mo are moderate, high and moderate, respectively. The overall intensity and extent of homogeneity of the {111}-fiber have marked influence on both the σYS and uniform elongation values. The alloys reveal the presence of two slopes in true plastic stress–strain curves and follow typical Ludwigson relation. The deformation behavior in low strain regime is associated with formation of uniform and finely spaced slip lines within the grains as a result of very small fraction of strain localization. On the other hand, main attributes of high strain regime are penetration of a few coarse slip lines across the grain boundaries along with large volume fractions of deformation twins and strain localization. The overall nature of differential curves of all the alloys is quite different although these curves consist of typical three stages (I, II and III) of work hardening. The nature of differential curves indicates different deformation mechanisms associated with these alloys during uniform elongation. Uniform elongation values of the alloys have been explained based on dynamic recovery coefficient using Kocks–Mecking–Estrin analysis.

This work describes microstructure, texture, and orientation-dependent flow behavior of Ni-16Cr and Ni-16Mo alloys in hot rolled and annealed condition. The high and low stacking fault energy values associated with Ni-16Cr and Ni-16Mo result in partial recrystallization after recovery and presence of twins in recrystallized grains, respectively. Both the alloys display two slopes in the true plastic stress–strain curves and follow Ludwigson relation, however the deformation mechanisms of both the alloys associated with two slopes are different. The low-strain regime of flow curves of the alloy Ni-16Cr is associated with uniform and finely spaced slip lines within the grains along with very small fraction of strain localization. On the other hand, a few slip lines appear to cross the grain boundaries in high-strain regime with a favorable angular deviation between adjacent grains along with large fractions of strain localization (2 to 5 deg low-angle grain boundary). On the other hand, the low-strain regime of the alloy Ni-16Mo is related to the presence of uniformly and finely spaced slip lines and small fractions of both the deformation twins as well as strain localization. The main features of high-strain regime of the alloy Ni-16Mo exhibit large volume fractions of deformation twins and strain localization along with few coarse penetrating slip lines across the grain boundaries. Sample orientation-dependent ductility of both the alloys has been explained based on dislocation storage capacity and dynamic recovery coefficient using Kock–Mecking–Estrin analysis.

The effect of 2.5 wt.% Cu addition to Ti6Al4 V alloy in regard to its structural phases and properties has been investigated. Alloying with 2.5 wt.% Cu increased the yield strength (Y.S) by 400 MPa. Solution treatment at 1283K and successive aging treatment at 773K has resulted in fine α lath structure with a very less fraction of β phase. Ageing treatment at 773K for 4 hrs and 40 hrs produced tetragonal nano Ti2Cu precipitates. The number of Ti2Cu phase increased with holding time. The precipitates were formed preferentially at the lath boundaries. The highest Yield Strength was obtained in the solution treated state without aging. Effect of strengthening by Ti2Cu was revealed in hardness measurement.

Present work describes microstructure-texture-mechanical property anisotropy correlation of Ni-16Cr and Ni-16Cr-16Mo alloys in hot rolled and annealed condition. The high and low SFE values associated with Ni-16Cr and Ni-16Cr-16Mo alloys result in partial recrystallization after recovery and presence of twins in recrystallized grains, respectively. Both the alloys display two-slopes in the true plastic stress-strain curves and follow Ludwigson relation. However, the deformation mechanisms of both the alloys are different. Sample orientation dependent ductility of these alloys has been explained based on dislocation storage capacity and dynamic recovery coefficient using Kock-Mecking-Estrin analysis.

Present work describes a correlation amongst texture, in-plane anisotropy in tensile properties and yield locus in Ni–20Cr–8Fe alloy. The alloy exhibits high and moderate values of in-plane anisotropy and anisotropy index, respectively. This has been attributed to the presence of moderate overall intensity of texture as well as partially recrystallized microstructure. The tensile properties evaluated in five sample directions, namely the 0° (longitudinal or L), 22.5°, 45°, 67.5° and 90° (transverse or T) to the rolling direction, display two slopes in true plastic stress–strain curve and follow a Ludwigson relation. At low strains, sample displays the presence of annealing twins and less strain localization (1.5–3.5° boundaries) while the formation of deformation twins and high strain localization are observed in high strained region. The 67.5° orientation sample shows relatively low ductility and low work hardening exponent. This has been explained using Kock–Mecking–Estrin analysis based on higher degree of dynamic recovery/glide softening and fluctuations in work hardening rate during stage II.

Current study has been carried out to compare the development of microstructure in deformed zone of M50 bearing steel during abrasion. Three-body abrasive wear was carried out using abrasive test apparatus as per ASTM G 65-85 with applied load of 13 kg. Silica sand of dimension 200±50 μm was used as abrasives. The effect of deformed features in abrasion resistance has also been delineated. Crystallographic lath pocket oriented sheared features were observed after abrasion of martensite. Very less fractions of crystallographic sheared features were observed after abrasion of ferrite. The abrasion did not produce dislocation cell structure in ferrite. Ferrite associated just more dynamic recovery while martensite was concomitant to greater dynamic recrystallization. Major toughness enhancement by abundant sheared features and dynamic recrystallization in martensite resulted in higher abrasion resistance of martensite than ferrite.

This work describes a correlation among texture, in-plane anisotropy in tensile properties, and yield locus in Ni-based Hastelloy C-276 alloy. The alloy exhibits moderate values of in-plane anisotropy and anisotropy index, which has been attributed to the presence of moderate overall intensity of texture. The alloy displays two slopes in true plastic stress–strain curve and follows a Ludwigson relation. At low plastic strains, the sample displays the presence of annealing twins and less strain localization at grain boundaries, while the formation of deformation twins and high strain localization within the deformation twins and at the grain boundaries are observed in a high-strained region. The 45-deg and 67.5-deg orientation samples show relatively low ductility and low work-hardening exponent. This has been explained based on dislocation storage capacity and dynamic recovery coefficient using Kock–Mecking–Estrin analysis.

The goal of the present study was to characterize the relative stability of near Cube, {001}〈100〉 orientations under plane strain deformation and then to validate the experimental observations with available deformation texture models. For the first part, single crystal exact Cube and Cube rotated along the rolling (RD), transverse (TD) and normal (ND) directions were deformed to approximately 25, 60 and 80 % reductions in the channel die and deformed samples were characterized elaborately by both bulk and microtexture measurements. A strong pattern emerged for relative Cube stability, stability increasing in the order of 5° TD–exact Cube–5° ND–10° TD–5° RD, a pattern relatively not affected by the extent of strain. The Cube instability was accommodated by the strain localizations and at the early stages the extent of micro-textural instability was reflected on the measured (from the deformation) textural softening. The rotation of the near cube was generally along TD, except for RD rotated Cube. Though classical full constrain Taylor model failed to capture the trends of both rotation and relative Cube stability, the Grain Inter-action (GIA)-Split-up method could capture both effects approximately. It should be noted that the matching of the experimental trends were approximate and with several subtle contradictions (for example, the GIA model predicted less stability for 10° TD over 5° TD, while experimentally the reverse was observed), but the overall method is far better than classical Taylor and indeed has shown the best results in the relative Cube stability during deformation.

The strength-to-weight ratio offered by AA6XXX alloys and their enhanced mechanical properties have become crucial criteria for their use in light weight military vehicles, rockets, missiles, aircrafts, and cars, used for both defence and civil purpose. The focus of this review paper is to put together the latest knowledge available from various sources on alloy design, industrial processing, development of properties, and potential use of AA6XXX alloys. The direct chill (DC) cast AA6XXX wrought alloys which are subsequently processed by fabrication process like hot working, cold working, process annealing, and age hardening heat treatments are the foci of this review though designation section also contains the designations of cast alloys to provide the reader a broad overview on designation. World-wide accepted designations are briefly tabled along with their alloying elements. The effects of the alloying elements which are generally used for AA6XXX wrought alloys are discussed incorporating their interactions during wrought AA6XXX alloy fabrication. The significance of the alloying and also the processing to develop the certain properties and the underlying strengthening mechanisms are discussed. The frequent and versatile uses of these AA6XXX alloys for the structural applications both in defence and civil purpose are put forth.

Electron backscattered diffraction investigations on just fully recrystallised orientation image microstructures, showed that the cube-oriented grains had the largest size in all microstructures of an aluminium alloy, which have potential use in the cartridge case manufacturing for defence purpose. The simulation of cube microstructure and texture of that aluminium alloy was tried. The recrystallisation texture and microstructure simulation by the 3-D cellular automaton model with the consideration of highest mobility of 40o grainboundary, predicted the volume fraction of the cube texture orientation which was validated by experiment. Defence Science Journal, 2010, 60(3), pp.330-336 , DOI:http://dx.doi.org/10.14429/dsj.60.361

The recovered cold rolled microstructure obtained from orientation image microstructure of Al-4%Mg-0·5%Mn alloy (AA5182 alloy) was superimposed on the grid of cellular automata based microstructure model. The Taylor factors of deformed/cold rolled orientations were considered as the driving force for recrystallization. The local development of recrystallized microstructure and texture were simulated with orientation dependent grain boundary mobility and compared with the experimental results.

AA7475 alloy was deformed up to 25% elongation in INSTRON at 788K. The grain boundary sliding due to this superplastic deformation was measured by Scanning Electron Microscope. The microstructure and texture development due to this deformation at elevated temperature was analyzed from the Orientation Image Microstructures i.e. the Electron Back Scattered Diffraction Image. The Orientation Image Microstructures revealed that superplastic deformation was associated with recovery and recrystallization in-situ process.

Elastic modulus anisotropy with respect to sheet rolling direction was calculated, using X-ray diffraction determined texture components and their known individual anisotropies, for a deep drawing grade steel in the cold rolled as received and three heat treated conditions. The calculated elastic modulus anisotropy was compared to mechanically measured modulus values, at 0, 45 and 90° to the rolling direction, and ultrasonic velocity anisotropy, measured using an electromagnetic acoustic transducer (EMAT) system. It was found that the EMAT velocity anisotropy matched the measured modulus variation with angle, with differences between the as rolled and heat treated conditions being observed. However the predicted modulus variation did not show much difference between the as rolled and heat treated conditions, despite different textures being measured, resulting in a slight discrepancy with the EMAT velocity and measured modulus values at 90° for one heat treatment condition.

This paper introduces an advanced recrystallization model, based on the principles of cellular automata. The model employs a scalable subgrid technique for efficient tracking of local variations during recrystallization and provides excellent statistics of grain size and texture after recrystallization. Grain boundary nucleation, transition band nucleation and particle-stimulated nucleation were incorporated in the model. This model can interface with other microstructural models, such as a deformation texture model, a dislocation density based flow stress model and a precipitation model. The sensitivity of the model with respect to minute changes of microstructure and microchemistry was tested. Finally, a through-process exercise was conducted to assess the performance of the model in multi-step simulations.

A more refined 3D cellular Automata (CA) algorithm has been developed which has increased the resolution of the space and reduced the computation time and can take care of the complexity of recrystallization process through physically based solutions. This model includes recovery, condition for nucleation and orientation dependent variable nuclei growth as a process of primary static recrystallization. Incorporation of microchemistry effects makes this model suitable for simulating recrystallization behaviour in terms of texture, kinetics and microstructure of different alloys. The model is flexible to couple up with other simulation programs on a common database.

The present study describes the development of microstructural and textural trends with and without process annealing of the Cu-30Zn brass. Process-annealing refines the grain size and randomizes the crystallographic texture. The best benefits of grain refinement and randomization of texture have been obtained in process-annealing after early stage of deformation. The crucial advantages of (random + Bs) texture strengths in formability of final cold rolled gauges and annealed sheets have also been highlighted.

The hot rolled AA3104 ingot was cold rolled to 40%, 66%, 80% and 90% reductions. The cold rolled sheet was subsequently recrystallized at two different annealing temperatures of 573 K and 773 K. The bulk texture developments, both deformation and subsequently after recrystallization, were measured by X-ray ODFs (orientation distribution function), while recrystallized (and in few cases the partially recrystallized or recovered) samples were studied by SEM-EBSD (scanning electron microscope based electron backscattered diffraction). Deformation increased the deformation texture components. The deformation texture variation was modelled using Taylor type deformation texture models. The identification of the source of recrystallized grains was possible by following proper conventions even in the fully recrystallized state. The sources of recrystallized grains were divided in various categories — (I) particle stimulated nucleation grains, (II) grains originating from deformed grains or bands, (III) grains developing from extended recovery and (IV) others (grains without a ‘confirmed’ identity). All categories had their own texture. The presence of these categories qualitatively defined the recrystallization textures and microstructures, as verified by cellular automaton modelling.